Laser line generating device

ABSTRACT

A self-contained line generating device uses a laser diode and a lens to project a fan-shaped beam of visible light. The lens is useful for receiving light and transmitting light in an asymmetrical planar beam. The light is useful for aligning object in a vertical or a horizontal line. The generator also includes a substantially flat face and leveling devices for leveling and orienting the generator onto a flat surface. Retractable pins enable a user to easily mount the line generator onto a wall and align objects.

This application claims the benefit of priority under 35 U.S.C. § 119(e)to the filing date of U.S. Provisional Application 60/291,135, filed onMay 15, 2001, of the same title, which is incorporated by reference inits entirety, and this application is a continuation application of U.S.patent application Ser. No. 10/141,392, filed May 7, 2002, (pending),the entire contents of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Alignment of surfaces is a perennial problem in a variety of fields,ranging from construction to interior decorating. Alignment is necessaryfor walls that should be perpendicular to a floor, or otherwise plumb.Masonry and brick-laying practitioners are well aware of the importanceof plumbed and aligned surfaces and chalk lines. A home interiordecorated with pictures and other wall ornamentation makes a much betterappearance when the ornamentation is aligned, especially with respect tovertical or horizontal alignment. Many mechanical and electricalalignment devices are available, and some laser devices are available.Some of these products are cumbersome, others are not as useful as theycould be. Chalk lines, for instance, are sometimes undesirable for usein finished, interior areas.

One aspect of alignment-product performance, and in particular oflaser-alignment products, that could be improved is the width,brightness and straightness of the laser light. A visible, straightlaser line is acceptable, but may be limited in its brightness over adistance, and may also tend to defocus and become dimmer as a user worksaway from the source of the laser. Rotating lasers are used to projectlines on walls perpendicular to the direction of propagation of thelaser. Thus, such devices may have limited utility or may not work inconfined spaces requiring a longer alignment tool.

Moreover, a conventional laser is not well-equipped for projecting aflat or planar beam of light. The essence of laser light is that it iscoherent or substantially monochromatic, that is, of a single wavelengthor a narrow wavelength band. Thus, when a beam of laser light isrefracted through a prism, the prism output is not a spreading of thebeam as with ordinary “white” light, but rather a coherent, focusedbeam, very similar to the input. The laser beam is thin and is usefullyonly visible when projected onto a surface.

Another aspect that could be improved is the inability of laser devicesto work around obstructions. That is, if a wall-hanging, such as apicture frame, interrupts the laser beam, it may be blocked from furtherprojection. Therefore, it is necessary to mark locations or heights, oneby one, rather than working with the actual objects, in order to alignthem. Obstructions may include moldings placed in a doorway, pictureframes in the way of those being aligned on one horizontal line, theoperator of the device, other obstacles, or even textured or stuccoedsurfaces on interior walls.

There are devices that direct a laser beam parallel to but away from asurface requiring alignment. A marker device or detector component isthen used to sight the beam and mark corresponding locations on the walladjacent the beam. Use of such a device requires multiple components andat least two people, one to align the laser and another to mark thewall. Moreover, the wall itself requires marking with this method.

A conventional laser beam projector is thus not able to project a laserline on the wall on which it is mounted, nor can it go aroundobstructions. A laser alignment beam mounting on the wall wherealignment is needed would allow a person seeking alignment, whether acarpenter, a painter, or an interior decorator, to accomplish his or hertask in a quicker and easier fashion. The ability to work aroundobstacles would save much time and effort. Finally, such laser alignmentdevices must be aligned themselves, and are typically equipped with atripod and a sophisticated leveling device so that they read true forhorizontal and vertical plumbs. While leveling is necessary, suchsophistication as a tripod adds to the expense and bulkiness of theleveling device. What is desired is a convenient, easy-to-level laserdevice useful for aligning objects.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the invention is a laser line generating device. Theline generating device includes a housing. Within the housing aremounted a light source and a power supply connected to the light source.There is a projection lens that receives light and projects the light inthe shape of a fan. There is also at least one reference level on anoutside of the housing. The light is projected substantially along itsdirection of propagation onto the wall on which it is mounted. Anotherembodiment is a line generating device. The line generating deviceincludes a housing and a light source mounted within the housing. Thereis a power supply connected to the light source, and there is aprojection lens that receives light and projects the light in adirection of propagation in the shape of an elongated fan thatsubstantially lies within a plane that is oriented at an angle withrespect to the direction of propagation.

Another embodiment is a method for projecting a fan-shaped laser lightonto a surface. The method includes focusing a light into a fan shapethat substantially lies within a plane, and projecting the fan-shapedlight in a direction of propagation that is oriented at an angle withrespect to the plane. Another embodiment is a line generating device.The line generating device includes a housing and a light source mountedwithin the housing. Within the housing there is also an optical systemthat receives light and projects the light as a fan-shaped beam thatlies substantially within a plane and forms a visible line at anintersection of the beam and a surface of interest. Another embodimentis a lens for receiving and projecting light. The lens includes anoptical material, and has at least one corner radiused from about 0.030to about 0.060 inches. The lens is adapted to receive light and totransmit light in a fan-shaped beam.

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these drawings in combination with the detailed description ofspecific embodiments presented herein.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an isometric view of an outside of an embodiment of a laserline generator according to the present invention.

FIG. 2 is an alternate view of the generator of FIG. 1.

FIG. 3 is a cutaway isometric view showing the inside of the generatorof FIG. 1.

FIG. 4 is a view depicting the bottom of the generator of FIG. 1.

FIG. 5 is another view depicting the bottom of the generator of FIG. 1.

FIG. 6 depicts an embodiment of optics to be used with the laser lightgenerator of FIG. 1.

FIG. 7 depicts a side view of the workings of a second embodiment oflaser light generator optics to be used with the laser line generator ofFIG. 1.

FIG. 8 depicts a top view of the workings of the laser light generatoroptics of FIG. 7.

FIGS. 9A-9C depict a laser line generating device projecting the laserlight in a narrow asymmetric beam or fan and aligning objects on a wall.

FIGS. 10 and 11 depict lens geometries useful for lenses in the presentinvention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The present invention is better understood by reference to the figuresand description below. FIG. 1 presents a view of a laser alignmentdevice and generator 10. The generator comes in a housing 12, which maybe made of plastic or other suitable material such as metal. Itpossesses a handgrip area 14 for handling, the area preferably made ofan elastomeric substance for easier gripping. The generator has a firstleveling device 16, a spirit level or “bubble” for orientation orleveling in one plane, such as horizontal or vertical. It also has asecond leveling device 18, for orientation or leveling in a second planeperpendicular to the first plane. The housing also contains a protectivedoor 20 with a linked switch for turning on the laser light source whenopening the door for access to the laser beam. The generator also mayhave one or more sliding levers 22 suitably mechanically connected forextending or retracting one or more pins 26 from the generator bottom28. Each pin desirably penetrates into a surface, such as a drywall orlumber surface, to suspend and hold the laser generator on the surfacewhile it is in use. FIG. 1 depicts the door 20 in an open position and aprojection lens 24. The door or aperture 20 provides an exit for thelight generated within the housing, and in the open position, does notsubstantially block the exit of light from the housing.

As shown in FIG. 1, a preferred projection lens 24 includes a roundedcorner 25 on its front face 27. The effect of the lens is to shape thelaser light into a planar, fan-shaped “comet beam” or fan shape. Theintensity of the light and the shape of the beam may be asymmetric, inwhich one side of the “comet” may be larger and brighter than the otherside. The fan shaped beam is then routed so that the less bright side ofthe lens is nearest the wall of interest, and the brighter side is awayfrom the wall. In this orientation, the fan-shaped beam of light willpropagate a long distance from its origin, and the laser light will beusable a long distance away from the laser line generating device.

The laser light generated by the laser line generator preferably exitsfrom the top, curved corner of the lens. The radius of the corner isdesirably from about 0.030 inches (0.75 mm) to about 0.060 (1.50 mm)inches, and preferably about 0.047 inches (1.2 mm). The height of therounded corner of the lens is desirably one or two inches above thebottom surface of the laser line generating device. When the beam or fanof light exits the lens, it forms a thin plane in the length-wisedirection of the device, and the beam forms a plane from the top, curvedcorner of the lens downward, to the wall or other surface on whichalignment is sought. Because the light is now a plane, rather than athin pinpoint, it is able to project over and beyond obstacles, allowinga user to align several objects without having to move them.

In the embodiments shown, the laser light projects in the direction ofthe alignment surface, a generally flat, planar bottom support surface.The direction of propagation is the direction the light travels,generally parallel to the wall on which the laser line generating deviceis mounted. The fan-shaped aspect of the beam is perpendicular to thewall, and is preferably no higher than the height of the lens 24 abovethe wall. The laser light generating device and its lens are mounted onthe wall, and the fan-shape of the beam extends from a height of thelens above the wall to the wall surface itself, in a very thin plane,about 1/32 of an inch thick. The plane of the fan-shaped beam is alsoperpendicular to the flat bottom surface of the laser line generatingdevice.

FIG. 2 depicts the same device with the door 20 closed, and with alinked internal switch (not shown) open, and the laser thus off. Thefigure depicts the generator 10, housing 12, gripping surface 14 andlevels 16, 18 with pin lever 22 raised so that the pin remains insidethe housing and the laser generator is not suspended on a wall or othersurface. The door or aperture 20 may also be a switch for the powersupply of the laser line generating device. In the position shown inFIG. 2, with the door closed, the switch is preferably in a closedposition and there is no power supplied from the power supply to thelight source. In this position, the door acts as a lens cover andsubstantially blocks the exit of the device.

FIG. 3 depicts a cutaway view of the interior of the laser generator,showing a supporting structure 34, 40 for levels 16, 18, and alsoshowing an area for a power source or battery 32, a laser diode 42, alens 24, and a circuit board 36. FIG. 4 more clearly depicts a view fromthe bottom or flat face 30 of the generator 10. The bottom surfacedesirably has a door 52 for access to a battery or power source for thegenerator. Also shown are holes 54 for the retractable pins 26 used tosecure the generator to a wall or a surface. A notch 56 may also beuseful for aligning or orienting the generator on a surface. FIG. 5depicts the bottom of the laser generator with the pins retracted, witha better view of holes 54.

A method of practicing the invention includes providing a surface, suchas a wall wherein orientation with a line is desired, and also providingthe laser generator. A user mounts the laser generator 10 via its flatsurface and one or more pins onto the wall and orients it in one or moreplanes, depending on the number of pivot points and on the number ofreference levels provided on the generator. Typically, a user will mountthe generator 10 with a pin or retainer placed through a pivot point onthe flat surface of the generator. The reference level such as thebubble level 18 is then used to orient and true the generator in oneplane, for instance, the vertical plane. The second bubble level 16 maybe used if the user wishes to orient the generator in a horizontalplane. When the user is satisfied with the orientation, the user turnson the generator 10, projecting a laser beam from the vertical orhorizontal plane of the device. In one embodiment, the generator isturned on by opening the lens door or aperture. In addition to theretractable pins used as pivot point, the device may have apertures orholes placed in the flat bottom surface. In this method, a user insertspins or nails through the holes and mounts, levels, and supports thelaser generator using those pins.

A desirable feature of the invention is that the output of the generatoris not merely a linear beam of light, but rather a fan-shaped beam. Thefan-shaped beam propagates along the surface of the wall in thedirection of propagation. Because the plane of the beam runsperpendicular to the wall along the length of the beam, the line ofintersection between the beam and the wall forms a visible line ofalignment. With a fan-shaped beam, the laser light is able to projectover and beyond obstacles, such as moldings placed in a doorway, pictureframes in the way of those being aligned on one horizontal line, orother obstacles, such as a wavy or stuccoed surface on an interior wall.With a conventional laser generator, these obstacles must be removed orthe laser itself must be repositioned to avoid each obstacle. Of course,moving and relocating the laser alignment tool destroys the continuityof the line of alignment. Moreover, a conventional laser is notwell-equipped for shaping the laser beam into a fan. The essence oflaser light is that it is coherent, that is, of a single wavelength or anarrow wavelength band. Thus, when laser light is refracted through aprism, the prism output is not a spreading of the beam as with ordinary“white” light, but rather a coherent, focused beam, very similar to theinput. The present invention overcomes this obstacle by sending a sharp,focused pinpoint of light through a specifically constructed lens tocreate a flat planar, fan-shaped beam of light.

It is also noteworthy that the axis of alignment, such as the alignmentof pictures on a wall, is substantially parallel to the direction ofpropagation of the laser light. By contrast, a conventional and lessuseful method is to project a laser light perpendicular to a wall orother surface in which alignment is desired, and perpendicular to thedirection of propagation. With the instant laser line marking device, auser projects a fan-shaped beam in a propagation direction that issubstantially parallel, rather than perpendicular, to the surface onwhich alignment is desired, the fan-shaped dimension of the beam beingperpendicular to the wall.

As seen in FIG. 9 a, the laser line generating device propagates lightin the length-wise direction of the laser line generating device 10. Thedirection of propagation, shown by arrow 84, is substantially parallelto the wall, with the fan-shaped aspect of the beam being perpendicularto the wall. In one example, if a narrow fan projects from a linemarking device according to the present invention, the beam is“substantially parallel” if it is substantially parallel for at leastseveral lengths of the line marking device in the direction ofpropagation of the laser. It is substantially parallel because even a“narrow” fan spreads rapidly and the beam is no longer strictlyparallel. The device and the beam are easily distinguished, however,from a beam that has a direction of propagation perpendicular to thewall, such as shown in U.S. Pat. No. 5,208,438.

The laser light exits the lens or prism in an elongated fan in adirection of propagation. The direction of propagation, as discussedabove, is substantially parallel to the surface on which alignment isdesired. The width of the fan, however, is perpendicular to the surface,and the intersection of the beam with the surface generates the visibleline of alignment that the user seeks. It is this width that allows thefan to project over and beyond obstacles. That is, even though anobstacle may partially obscure the fan-shaped beam of light, at leastpart of the fan-shaped beam extends above and beyond the obstacle, and auser may continue to align objects on which alignment is desired.

FIG. 6 depicts an embodiment of the invention, in which a laser diode 60emits coherent laser light, such as, coherent laser light at 635 nmwavelength. The light is collimated into an ovate shape by collimationoptics 62, for instance at least one collimating lens, by techniqueswell known to those skilled in optic arts. The ovate beam then enters aprojection lens 64 from the right side in FIG. 6, desirably at an anglein which total internal reflection will occur, that is, all the incidentlight will be reflected rather than refracted from the back face of thelens. It has been found that this phenomenon is reinforced further ifthe back surface 66 of the lens is mirrored. The phenomenon is alsoreinforced if a corner of the lens or prism is radiused as mentionedabove. When the light emerges from the radiused corner 65 of theprojection lens 64 in FIG. 6, it is in the shape of a narrow beam orfan, rather than a single point or beam of light, and is able to extendaround and beyond obstacles for the convenience of a user. In oneembodiment of the invention, the angle A between the mirror surface ofthe collimating lens and the incident light from the laser diode sourceis from about 60 to about 65 degrees, preferably about 63 degrees, formaximum reflection of light through the lens, rather than refraction atangles that detract from the performance of the generator. In thisdepiction, the light 68 is planar within the plane of the paper, when itleaves the lens. In one embodiment of the invention, the laser diode,the collimation lens, and the projection lens are contained within asingle element, such as a laser diode with included collimating optics.

In one embodiment shown in FIG. 6, an aspherical projection lens is madefrom optic grade glass, in the form of an equilateral triangle with theback face mirrored. Desirably, the lens is about 0.45 inches on a side,with one corner 65 radiused to about 0.030 to about 0.060 inches and theother corners rounded to a radius of 0.005 to 0.015 inches. With thisgeometry, the lens or prism is able to focus an incoming ovate beam intoa planar, thin, fan-shaped beam that is useful for aligning objects.

FIG. 7 depicts a side view of another embodiment of the invention, inwhich a laser light source 70, such as a laser diode, emits laser light,which is collimated into an ovate shape by collimating optics 72 andthen sent to an aspherical projection lens 74 with one corner 75radiused as mentioned above for projection of a narrow fan of light 76.In one embodiment, the axes of the ovate-shaped beam sent to the lensare about 3/16 inches by about 1/16 inch. The planar, fan-shaped beam 76emerging from projection lens 74 is than about 1/32 inch thick. Notethat the top corner 75 on the face of the lens in FIG. 7 is radiusedfrom about 0.030 to about 0.060 inches, and preferably about 0.047inches. FIG. 8 depicts the same embodiment in a top view, in which therounding may not be observable. The source of laser light 70 generatesvisible laser light and the collimating optics 72 shape the light into anarrow beam. From the top view, the beam of light is very thin and isabout the width of the projection lens 74, 0.4 inches wide. From theside view, the projected light is a thin beam; from the top view, theprojected light is a thin fan.

One embodiment of the invention features a lens, such as the lensesdepicted in FIGS. 7 and 8, that is about 0.4 inches (10 mm) square, andabout 0.1 inches thick (2.5 mm) in the direction of propagation, that isable to focus the incoming laser light beam and reflect it into a planarfan shape. The lenses are aspherical, cylindrical lenses. The lens maybe made from one of several optical-grade clear, highly transparentmaterials, including BK7 glass having an index of refraction of about1.5168 and a Vd of 64.17. In another embodiment, acrylic resin having anindex of refraction of 1.4917 and a Vd of about 55.31 is useful. It hasbeen found that the lens works better if the exit face has only onecorner radiused about 0.047 inches, with the other faces being radiusedfor normal manufacturing custom, to about 0.005 to about 0.015 inches.

FIG. 9A demonstrates the use of an embodiment of a laser generator 10according to the present invention, in which a fan-shaped beam 76 isable to align a first picture frame 78 on wall 77. The generator isconvenient to use because it projects a laser beam on the wall adjacentthe generator. The beam is able to overcome obstacles such as doormoldings 80 with its fan shape and extend above the molding withsufficient clarity to align another object, such as picture frame 82. Itis able to overcome these obstacles because the corner from which thelight exits is one or two inches removed or offset from the wall,allowing a fan or beam of light to form. The direction of propagation 84is in the direction from the generator to the objects on which alignmentis desired, such as picture frames. At the same time, the width of thefan is perpendicular to the wall 77 on which the paintings are hung oron which, more generally, alignment is desired. The fan-shaped beam 76intersects the wall 77 and the light is visible on the wall at theintersection 79 of the fan-shaped beam 76 with the wall 77. In oneembodiment, the housing of the laser line generator is a support facethat substantially extends along a first planar surface, such as wall77, and the fan shaped beam 76 substantially lies within a second planarsurface, such as the plane of light 76. The second planar surface mayintersect the first planar surface at an angle. The angle may preferablybe 90°, or a right angle between the fan-shaped beam and the surface onwhich objects are to be aligned.

The “comet” effect means that the intensity of the planar fan is lessnearer the wall and greater away from the wall, so that the beam is ableto usefully travel further, and enable a user to align objects atgreater distances. Thus, in the embodiment shown in FIG. 9B and FIG. 9C,the intensity of the laser light will be greater at outer edge 87 thanat the inner edge 85 where the fan-shaped beam intersects the wall 77while the beam is used to align object 82, such as a picture frame.There is no practical limitation to the distance the fan-shaped beam cantravel. Laser diodes of 5-15 mW can be successfully used to projectbeams 30-50 feet long along painted wall-board surfaces. In oneembodiment, the fan-shaped beam is projectable as a visible lineextending at least about 5 lengths of the housing away from the housingfor aligning objects. FIG. 9C depicts the comet effect or asymmetry ofthe planar fan, the intensity of light being greater in the portion ofthe beam that is further away from the wall or plane of interest.

FIGS. 10 and 11 depict geometries of projection lenses that can beuseful in connection with this invention. FIG. 10 depicts the sag orcurvature of the exit face of the lens (z-direction deviation plottedagainst the depth or y-coordinates of the lens), while FIG. 11 depictsthe overall profile or curvature of the lens surface. While theseparticular embodiments work well, the invention is not limited to theseembodiments, and other embodiments will also suffice.

While this invention has been shown and described in connection with thepreferred embodiments, it is apparent that certain changes andmodifications, in addition to those mentioned above, may be made fromthe basic features of this invention. For instance, lenses may be madefrom glasses other than BK7 and plastics other than acrylic, so long atthey are transparent and to a degree sufficient to be used as a lens orarticle for transmitting light. While embodiments of triangular prismsand relatively flat square lenses have been successful, other polygonsor aspherical embodiments may also be used, so long as they have aradiused corner of about the requisite dimension. In other embodimentsof a laser generating device, alignment may be made in lines or planesthat are diagonal, rather than horizontal or vertical. While one or morepins may be used to hold the generator onto a wall, other devices may beused as retainers. These devices include, but are not limited to, astring or a wire, a fastener, tape, putty-type substances or otheradhesives. While the laser line generator may be most convenient to usewhen pinned to a wall, it may also be mounted on a table, floor, orother flat surface, and used to project a line without being mounted ona wall. Many other variations of our invention may also be used withoutdeparting from the principles outlined above. Accordingly, it is theintention of the applicants to protect all variations and modificationswithin the valid scope of the present invention. It is intended that theinvention be defined by the following claims, including all equivalents.

1. A line generating device, comprising: a housing; a light sourcemounted within the housing; a power supply connected to the lightsource; a projection lens that receives light and projects the light inthe shape of a fan; at least one reference level on an outside of thehousing; and a pin that is movable from a first position, wherein thepin is incapable of contacting a surface exterior of the line generatingdevice, to a second position wherein the pin is capable of contactingthe surface.
 2. The device of claim 1, wherein the light sourcegenerates a laser beams.
 3. The device of claim 2, wherein the laserbeam has an asymmetric intensity pattern.
 4. The device of claim 1,wherein the housing comprises a support face that substantially extendsalong a first planar surface and the fan substantially lies within asecond planar surface that intersects the first plane surface at anangle.
 5. The device of claim 4, wherein the angle is about 90°.
 6. Thedevice of claim 4, wherein the light projects a line in a directiongenerally parallel to the first planar surface, the line extending in adirection of propagation of the light.
 7. The device of claim 1, whereinthe power supply is a battery mounted within the housing and switchablyconnected to the light source.
 8. The device of claim 1, wherein the atleast one reference level comprises a bubble level.
 9. The device ofclaim 1, wherein the at least one reference level comprises two bubblelevels oriented at right angle to each other.
 10. The device of claim 1,further comprising an aperture in the housing.
 11. The device of claim1, wherein a corner of the lens has a radius of about 0.030 inches toabout 0.060 inches.
 12. The device of claim 11, wherein the corner ofthe lens has a radius of about 0.047 inches.
 13. The device of claim 1,wherein the light in the shape of a fan is projectable as a visible lineextending at least about 5 lengths of the housing from the housing. 14.The device of claim 1, further comprising a collimating optics thatreceives light from the light source and focuses the light into an ovateshape for the projections lens.
 15. The device of claim 1, wherein theprojection lens is made from glass or plastic.
 16. The device of claim1, further comprising an aperture in the housing, the aperture providingan exit for the light and a lens cover switchably connected to the powersupply, wherein when the lens cover moves to a first lens cover positionthe light source is connected to the power supply and the lens coverdoes not substantially block the exit and when the lens cover moves to asecond lens cover position the light source is not connected to thepower supply and the lens cover substantially blocks the exit.
 17. Thedevice of claim 1, wherein the housing defines an opening through whichthe pin extends through when moving from the first position to thesecond position.
 18. The device of claim 1, further comprising a leverfor pushing and holding the pin into the surface.
 19. The device ofclaim 1, wherein the pin is mounted to the housing. 20-84. (canceled)